Topological Evolution in Mercury(II) Schiff Base Complexes Tuned through Alkyl Substitution - Synthesis, Solid-State Structures, and Aggregation-Induced Emission Properties
文摘
From two series of Schiff base ligands, (E)-N-(pyridine-2-yl)(CMe=NPhR) and (E)-N-(pyridine-2-yl)(CH=NPhR) [R = H, L1a, L1b; 2-CH3, L2a, L2b; 4-CH3, L3a, L3b; 2,6-(CH3)2, L4a, L4b; 2,6-(C2H5)2, L5a, L5b; 2,6-(i-C3H7)2, L6a, L6b; 2,4,6-(CH3)3, L7a, L7b], fourteen mercury(II) complexes, namely, Hg1a–Hg7a and Hg1b–Hg7b were synthesized. Their structures were established by single-crystal X-ray diffraction, and they were physically characterized by 1H and 13C NMR spectroscopy, ESI-MS, FTIR spectroscopy, elemental analysis (EA), and powder XRD (PXRD). The crystal structures indicate that the position and type of substituent can directly influence the formation of 1D → 3D supramolecular metal–organic frameworks through C–H···Cl and π–π interactions. Complexes Hg1a–Hg7a and Hg1b–Hg7b display deep blue emissions at λ = 401–428 nm in acetonitrile solution and light blue emissions at λ = 443–494 nm in the solid state. It is worth noting that Hg1a, Hg3a, Hg1b, and Hg3b exhibit good aggregation-induced emission (AIE) properties in CH3CN/H2O solutions.